1. Field of the Invention
The present invention relates to a die casting machine for producing a die casting product by charging molten metal, which has been injected from a plunger sleeve section provided in a metallic mold, into a product cavity section via a runner. The present invention also relates to a die casting method.
2. Description of the Related Art
As shown in FIG. 14, a die casting product is produced by the die casting machine 9 in such a manner that molten metal, which has been injected from the plunger sleeve section 922, is charged into the product cavity section 921 via the runner 923, so that the die casting product can be produced in the product cavity section 921. When molten metal is charged into the product cavity section 921, gas pressure in the product cavity section 921 is increased. Therefore, molten metal cannot be sufficiently filled in the product cavity section 921. In order to solve the above problem, gas remaining in the product cavity section 921 is discharged outside by the decompression device 94.
In the above die casting machine 9, in order to enhance the mold releasing property of a die casting product and a molding, which are respectively formed in the molding section 920 composed of the product cavity section 921, the plunger sleeve section 922 and runner 923, and, further, in order to enhance the lubricating property of the plunger chip in the molding section 920 and, furthermore, in order to enhance the heat reserving property of molten metal, the powder mold releasing agent 6 is supplied from the plunger sleeve section 922.
In this connection, recently, the die casting device 9 has seen wide application from a small size die casting product to a large size die casting product. Further, the die casting device 9 is used not only for a simple die casting operation such as conducting a die casting operation for a single die casting product but also for a complicated die casting operation such as conducting a die casting operation for a plurality of die casting products.
However, in the conventional die casting machine 9 described above, the powder mold releasing agent 6 is supplied only from the plunger sleeve section 922. That is, the product cavity section 921 is distant from the plunger sleeve section 922. Accordingly, there is a possibility that the powder mold releasing agent 6 may not sufficiently spread into the product cavity section 921.
Further, when the powder mold releasing agent 6 is supplied from the plunger sleeve section 922, there is a possibility that the powder mold releasing agent 6 may not be uniformly supplied to between the product cavity section 921 and the plunger sleeve section 922. The aforementioned problems may become remarkable in the case where a complicated die casting product is produced.
The present invention has been accomplished to solve the above conventional problems. It is an object of the present invention to provide a die casting machine and die casting method capable of supplying a powder mold releasing agent to a product cavity section, a plunger sleeve section and a runner in a well balanced condition so as to produce a die casting product of high quality.
One aspect of the present invention is a die casting machine comprising:
a metallic mold including a plunger sleeve section for injecting molten metal, a product cavity section for molding a die casting product when molten metal is charged into it and a runner for connecting the plunger sleeve section with the product cavity section;
a decompressing device for decompressing the plunger sleeve section and the product cavity section;
a powder supply source for supplying a powder mold releasing agent to the plunger sleeve section and the product cavity section; and
a powder discharging pin arranged in the runner in a retractable state, having a powder introducing passage connected with the powder supply source, wherein
the powder discharging pin includes a first opening section to open the powder introducing passage toward the product cavity section and a second opening section to open the powder introducing passage toward the plunger sleeve section, when the powder discharging pin proceeds into the runner.
The die casting machine of the present invention includes a powder discharging pin having a powder introducing passage connected with a powder supply source for supplying a powder mold releasing agent. In order to supply a sufficiently large quantity of powder mold releasing agent to the product cavity section, this powder discharging pin is arranged so that it can protrude into a runner located between the product cavity section and the plunger sleeve section.
The powder discharging pin includes: a first opening section which can open the powder introducing passage toward the product cavity section and a second opening section which can open the powder introducing passage toward the plunger sleeve section, when the powder discharging pin proceeds into the runner.
Due to the first and the second opening section, a plurality of discharging ports to the product cavity section and the plunger sleeve section are formed from one introducing passage of the powder mold releasing agent connected with the powder supply source. It is possible to directly supply the powder mold releasing agent toward the product cavity section and the plunger sleeve section from the plurality of discharging ports, that is, from the first and the second opening section.
Therefore, it is possible to uniformly spread the powder mold releasing agent to each portion including the product cavity section, the plunger sleeve section and the runner. Due to the foregoing, the powder mold releasing agent can be supplied in a well balanced state to the product cavity section, the plunger sleeve section and the runner in the metallic mold.
Due to the foregoing, for example, even in the case of a large die casting molding, the profile of which is complicated, or even in the case of a complicated die casting molding, in which a plurality of products are molded at one die casting operation, the above powder discharging pin can exhibit an excellent performance, and operation can be flexibly conducted.
When the plunger sleeve section and the product cavity section are decompressed by the decompressing device, the powder mold releasing agent can be more effectively supplied to the plunger sleeve section and the product cavity section.
The powder discharging pin is arranged in a retractable state with respect to the runner. Therefore, after the powder mold releasing agent has been supplied from the powder discharging pin, it is possible to retract this powder discharging pin. Therefore, when molten metal is charged into the product cavity section via the runner, it is possible to prevent the powder discharging pin from blocking the charge of molten metal.
Therefore, according to the die casting machine of the present invention, the powder mold releasing agent can be supplied in a well balanced condition to the product cavity section, the plunger sleeve section and the runner, and a die casting product of high quality can be produced.
Another aspect of the present invention is a die casting method in which molten metal is injected from a plunger sleeve section provided in a metallic mold and the injected molten metal is filled in a cavity product section via a runner so as to produce a die casting product, comprising the steps of:
decompressing the product cavity section and the plunger sleeve section before molten metal is injected from the plunger sleeve section, when a powder mold releasing agent is supplied to the product cavity section and the plunger sleeve section;
advancing a powder discharging pin, which is arranged in the runner in a retractable state and has a powder introducing passage connected with a powder supply source, into the runner;
opening a first opening section provided in the powder introducing passage of the powder discharging pin toward the product cavity section and also opening a second opening section provided in the powder introducing passage toward the plunger sleeve section ; and
discharging the powder mold releasing agent from the first and the second opening section.
In the present invention, before molten metal is injected by the plunger sleeve section, the powder mold releasing agent is supplied to the product cavity section, the plunger sleeve section and the runner by utilizing the powder discharging pin. When the powder mold releasing agent is supplied to each portion of the metallic mold, each portion is decompressed by the decompressing device.
Then, the powder discharging pin is advanced into the runner. In this case, the first opening section provided in the powder introducing passage of the powder discharging pin is opened toward the product cavity section, and the second opening section provided in the powder introducing passage of the powder discharging pin is opened toward the plunger sleeve section.
Then, the powder mold releasing agent flowing in the powder introducing passage from the powder supply source is discharged from the first and the second opening portion. Due to the foregoing, the powder mold releasing agent can be directly supplied from the first opening section toward the product cavity section and from the second opening section toward the plunger sleeve section.
Therefore, according to the die casting method of the present invention, in the same manner as that of the die casting machine described before, the powder mold releasing agent can be supplied to the product cavity section, the plunger sleeve section and the runner in a well balanced condition. Accordingly, a die casting product of high quality can be produced.
The present invention may be more fully understood from the description of preferred embodiments of the invention, as set forth below, together with the accompanying drawings.